Current techniques for positioning within the urban environment include the following:                Cellular:                    GPS, A-GPS, Time of Arrival, Radio Fingerprinting, Cell Global Identity, and Enhanced Cell ID.                        WiFi:                    Radio Fingerprinting, WiFi TOA, and Wireless Access Point Wardriving.                        GPS:                    DGPS, WAAS, A-GPS, and Laser Augmentation.                        
GPS is a space-based satellite constellation that provides constant, global geopositioning to the end user. A user's GPS device processes signals from three or more GPS satellites, and by way of trilateration provides latitude and longitude data. GPS may be global, but it is not ubiquitous because foliage, building edifices, and bridges all block GPS signals. The absence of GPS signals in places such as the urban core is problematic because high value applications for reliable positioning abound, yet no reliable solution exists. The urban core in major cities is also known as the “urban canyon,” because skyscrapers on both sides of the streets block GPS signals. Another common problem is multipath distortion in which signals bounce off many surfaces before reaching the user, resulting in vastly inaccurate positioning data.
PhaseNet is original equipment manufacturer (OEM) “plumbing level” technology that is integrated into device and infrastructure products such as those sold by Motorola, Cisco, D-Link, Nokia, Ericsson, HP, Agilent, and Intel. This OEM technology is primarily in the form of software modules, but it also includes custom hardware for Military “MILSPEC” and custom applications. Additionally, hardware reference designs for very minor chip level modifications (IP) at the transceiver level can improve the performance. Because of its interoperability, PhaseNet can include any number of the additional positioning methods listed above; however, PhaseNet can reside independent of these and still provide sub-meter positioning to the end user.
To overcome the limitations of the GPS system mentioned above, a GPS extension can be provided by PhaseNet. Furthermore, PhaseNet can create an entirely independent navigational capability by embedding positioning data into wireless networks that abound in the urban canyon. PhaseNet is an interoperable architecture; hence, it implements a capability to effectively coordinate disparate devices operating at different frequencies, and with different standards and protocols. This architecture is reliable, precise, scalable, dynamic, broad baseline, plug-and-play, secure and cost-effective.
Potential users include city visitors relying on in-car navigation systems that show onscreen location data provided by GPS. GPS fails when a traveler crosses the threshold into the urban canyon where unreliable signals show inaccurate navigation data or may be blocked entirely. However, urban drivers are well within reception of reliable WiFi, WiMax or cellular networks and PhaseNet positioning data embedded in the corresponding wireless signals provide the necessary positioning data.
First responders tending to an emergency on a city sidewalk, copier technicians needing proof of performance for 50 copiers on various floors of a downtown building, courier dispatch wanting to know the location of a the driver, and city workers ensuring a backhoe is not cutting gas or fiber optic lines are all examples of situations in which PhaseNet service can substitute for inadequate GPS capability.
The abundance of WiFi in urban settings provides an excellent example of how PhaseNet may leverage a robust and abundant signal source. For example, increasing deployments of individual WiFi access points by businesses and consumers make it difficult to walk through a downtown area without detecting WiFi signals. WiFi “sniffers” typically installed on personal computer (PC) operating systems constantly look out for WiFi sources. PhaseNet positioning data can be added to the inbound and outbound packets sent from these access points to alert the user that a WiFi spot is available. These PhaseNet positioning data are located outside the firewall, enabling users to receive the data even if they are not logged onto a network, thus enabling both secured and unsecured access points to provide positioning data.